The present invention relates to an optical apparatus such as a video camera, a digital still camera, and an interchangeable lens.
An optical apparatus has a lens barrel for accommodating lenses that is formed of a combination of a plurality of members (barrel-constituting members). The barrel-constituting members are often connected by screws to achieve easy assembly, reliable securing, and easy disassembly (see Japanese Patent Laid-Open No. 2001-290184 and Japanese Patent Laid-Open No. 2003-295249).
FIG. 11 schematically shows a video camera in the prior art. Reference numeral 101 shows a lens barrel, 102 a recording/reproduction unit, 103 an electric circuit board, 104 a liquid crystal display, 105 a battery, and 106 an external member.
The lens barrel 101 has flange portions 101a to 101c formed on its outer circumference for allowing connection of a plurality of barrel-constituting members placed in the direction of an optical axis by screws extending in a direction in parallel with the optical axis.
The lens barrel of the optical apparatus incorporates a number of members including a plurality of lenses, optical components such as an aperture and an ND filter, actuators for driving thereof, as well as a detector for detecting the position of an image stabilization lens unit or a movable optical component. On the other hand, the optical apparatus needs to be reduced in size and to have a shape with few protruding portions for the purpose of improved portability and storage.
The flange portions 101a to 101c of the lens barrel 101 for connection of the plurality of barrel-constituting members by screws as shown in FIG. 11, however, require convex portions 106a and 106b of the external member 106 that fit the protruding flange portions. Alternatively, the external member 106 is necessarily formed to be larger than the lens barrel 101 as shown by a broken line 106c. In other words, it is difficult to realize the optical apparatus which has a reduced size and a shape with few protruding portions.
Since the lens barrel is typically placed in an end portion of the optical apparatus to occupy a relatively large area thereof, the convex portions or the larger size of the external member close to the lens barrel significantly contributes to an increase in size of the overall optical apparatus.